Obama supporters react during an election night gathering in Grant Park on November 4, 2008 in Chicago, Illinois.

Photo: Joe Raedle, Getty Images

Obama supporters react during an election night gathering in Grant...

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U.S. President-elect Senator Barack Obama (D-IL) arrives to speak to supporters during his election night rally after being declared the winner of the 2008 U.S. Presidential Campaign in Chicago November 4, 2008.

Photo: Gary Hershorn, Reuters

U.S. President-elect Senator Barack Obama (D-IL) arrives to speak...

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President-elect Barack Obama waves as he takes the stage at his election night party in Chicago's Grant Park, Tuesday, Nov. 4, 2008.

Photo: Morry Gash, AP

President-elect Barack Obama waves as he takes the stage at his...

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Obama supporters react after projections show that Sen. Barack Obama will be elected to serve as the next President of the United States of America during an election night gathering in Grant Park on November 4, 2008 in Chicago, Illinois.

Photo: Justin Sullivan, Getty Images

Obama supporters react after projections show that Sen. Barack...

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Obama supporters react after projections show that Sen. Barack Obama (D-IL) will be elected to serve as the next President of the United States of America during an election night gathering in Grant Park on November 4, 2008 in Chicago, Illinois.

Photo: Joe Raedle, Getty Images

Obama supporters react after projections show that Sen. Barack...

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Obama supporters react after projections show that Sen. Barack Obama (D-IL) will be elected to serve as the next President of the United States of America during an election night gathering in Grant Park on November 4, 2008 in Chicago, Illinois.

Supporters of U.S. Democratic presidential nominee Senator Barack Obama (D-IL) react to news of election victory for Obama at his election night rally in Chicago November 4, 2008. Obama captured the White House on Tuesday after an extraordinary two-year campaign, defeating Republican John McCain to make history as the first black to be elected U.S. president.

Photo: Shannon Stapleton, Reuters

Supporters of U.S. Democratic presidential nominee Senator Barack...

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CHICAGO - NOVEMBER 04: Obama supporters hold up a sign which reads "We Have Overcome" as they gather in Grant Park during an election night gathering on November 4, 2008 in Chicago, Illinois. After nearly two years of presidential campaigning, U.S. citizens went to the polls today to vote in the election between Sen. John McCain (R-AZ) and Sen. Barack Obama (D-IL). (Photo by Scott Olson/Getty Images)

Photo: Scott Olson, Getty Images

CHICAGO - NOVEMBER 04: Obama supporters hold up a sign which reads...

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Sen. Barack Obama and his wife, Michelle, cast their votes at a polling place in Chicago.

Photo: Jae C. Hong, AP

Sen. Barack Obama and his wife, Michelle, cast their votes at a...

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Supporters of Democratic presidential candidate Sen. Barack Obama react as they watch election returns at an Obama field office in Philadelphia.

Photo: Matt Rourke, AP

Supporters of Democratic presidential candidate Sen. Barack Obama...

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ANCHORAGE, ALASKA - NOVEMBER 4: William Bouwens (R) helps his mother Alice Bouwens, 84, cast her vote November 4, 2008, at the Fairview Recreation Center in Anchorage, Alaska. After nearly two years of presidential campaigning, U.S. citizens go to the polls today to vote in the election between Democratic presidential nominee U.S. Sen. Barack Obama (D-IL) and Republican nominee U.S. Sen. John McCain (R-AZ). (Photo by Johnny Wagner/Getty Images)

Photo: Johnny Wagner, Getty Images

ANCHORAGE, ALASKA - NOVEMBER 4: William Bouwens (R) helps his...

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Sen. John McCain accompanied by his wife, Cindy, places his ballot into a box while voting in the 2008 presidential election at the Albright United Methodist Church in Phoenix, Ariz.

Photo: Stephan Savoia, AP

Sen. John McCain accompanied by his wife, Cindy, places his ballot...

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Democratic presidential candidate Sen. Barack Obama, D-Ill. talks to his daughter Malia as he casts his votes at a polling place in Chicago.

Voters line up outside the Coleman Young Community Center on Detroit's east side to cast their ballot in the 2008 presidential election on Tuesday, Nov. 4, 2008. (AP Photo/The Detroit News, John T. Greilick) ** NO SALES, DETROIT FREE PRESS OUT **

Democrat Barack Obama, the 47-year-old senator from Illinois who defined the 2008 presidential election as a clarion call for change, was elected in a landslide Tuesday night as the nation's first African American president.

His victory represented more than the shattering of a racial glass ceiling. After eight years of conservative control of the White House, it also heralded transformational changes in the nation's political landscape.

The selection of Obama and vice presidential running mate Joe Biden over Republican nominee John McCain and his running mate, Sarah Palin, was fueled by a huge turnout that saw voters in some battleground states waiting hours in line to cast their ballots.

It ended the longest and the most expensive presidential campaign in history, one in which Republicans, battered by the deep unpopularity of President Bush, lost states that had long been GOP strongholds.

The Democratic team, bolstered by a tidal wave of young, African American and independent voters, racked up wins in delegate-rich Florida and Ohio - highly contested states that went to Bush in 2004 - as well as Iowa, Colorado, New Mexico and Nevada. Virginia, which hadn't backed a Democratic presidential candidate since 1964, was in Obama's column.

Among the battleground states, McCain pulled out wins only in Georgia and his home state of Arizona, which he had been forced to defend when last-minute polls showed Obama closing. In Pennsylvania, which McCain had tried desperately to pry from the Democrats, Obama won easily.

With several states still to be decided, Obama had piled up 338 electoral votes, well more than the 270 he needed to become the nation's 44th president.

A crowd of more than 100,000 people that crammed into Chicago's Grant Park for Obama's victory party erupted into pandemonium as news spread of their candidate's win.

Many wept. Strangers hugged strangers. Others grabbed each other and jumped up and down for joy, waved flags or erupted into dance and song. Even talk-show host Oprah Winfrey was shown hugging friends on the Jumbotron to the sounds of the song "Only in America."

"It's like the best Christmas that ever was," said Jules Conway, 30, a DePaul University employee who joined the celebration in Grant Park. "We all went out and voted, and we all worked ... because this time, we realized it could make a difference."

In San Francisco, throngs swarmed into the streets to bang pots and pans, honk horns and cheer. At Vesuvio's, the North Beach bar, the crowd spilled onto the sidewalks waving bottles of champagne.

Obama took to the Grant Park stage emerged at 11 p.m. Chicago time to declare that "a new dawn of leadership is at hand."

"If there is anyone out there who still doubts that America is a place where all things are possible, who still wonders if the dream of our founders is alive in our time, who still questions the power of our democracy, tonight is your answer," he said.

"It's been a long time coming, but tonight, because of what we did on this day, in this election in this defining moment, change has come to America," Obama said.

He drew laughs as he told his two young daughters, Sasha and Malia, "You have earned the new puppy that's coming with us to the White House." And then the crowd grew quiet as he acknowledged his grandmother, Madelyn Dunham, who died Sunday at 86 - just two days short of seeing her grandson make history.

"I know my grandmother is watching, along with the family who made me who I am. I miss them tonight," Obama said.

Twenty minutes after the polls closed on the West Coast, McCain gave his concession speech to somber followers at the Arizona Biltmore Resort in Phoenix, with Palin at his side.

"My friends," he said, "we have come to the end of a long journey. The American people have spoken, and they have spoken clearly."

Acknowledging the pain of racism throughout the nation's history, he added: "This is a historic election, and I recognize the special significance it must have for African Americans."

Despite his 10-minute, gracious concession speech, the mood at the McCain-Palin election night party was by turns defiant, angry and frustrated. Much of the ballroom had cleared out by the time Obama gave his victory speech, which was not shown on the giant TV screens.

"Now the weight of the nation's destiny falls onto the Democrats," said David McClendon, a 52-year-old Phoenix artist. "And they can't kick around George Bush anymore. They'll have no one else to blame."

Democrats won more than just the White House on Tuesday. They also increased their majorities in both the House and the Senate, though still falling short of a filibuster-proof edge in the Senate.

Political observers said the party had benefited in down-ballot races from Obama's appeal to desert the Bush era and bet on a president whose political path was anything but traditional.

"America is transformed," said Bay Area pollster and Democratic consultant Phil Trounstine. "A nation once rooted in slavery has chosen an African American as its leader, demonstrating to all the world that here anyone may rightfully aspire to life, liberty and the pursuit of happiness."

The 2008 election campaign was one of the longest and hardest-fought in the nation's history. For Obama, it started on Feb. 10, 2007, when the freshman U.S. senator and former community organizer declared his candidacy at a rally in Springfield, Ill., telling his audience that even "in the face of impossible odds, people who love their country can change it."

Over the next 21 months, "change you can believe in" became the mantra of the Obama campaign, as he fought to depict first his rivals for the Democratic nomination and then his 72-year-old general election opponent as closely tied to failures at home and in wars overseas.

McCain tried to establish his own credentials for change. After winning the nomination, the Arizonan portrayed himself as a maverick who had bucked his Republican Party repeatedly in 22 years in the Senate. He barely mentioned Bush's name, and the GOP president made no campaign appearances for the nominee.

As McCain fell behind in the polls, the ex-Navy pilot who spent five years as a North Vietnamese prisoner of war summoned his reputation as a tireless campaigner who could not be counted out. He was given up for dead politically last year even before the first presidential primary, he reminded voters, and he voiced confidence that a late surge would carry him again.

The campaign's intensity was reflected in voter interest. The crush of people pouring into early-voting booths in the days leading up to Tuesday, plus the swarms going to the polls on election day, pointed toward a possible record turnout.

Against the backdrop of the economic crisis, expensive wars in Iraq and Afghanistan and a bitter national divide over abortion, religion and other social issues, the two teams' relentless stumping also turned this into the most costly general election in history.

The ascendancy of an African American to a major party nomination for president was inconceivable to many just a generation ago. But Obama, born to a white woman from Kansas and a black Kenyan, proved himself to be more than the sum of his race's legacy.

First as a community organizer on Chicago's impoverished South Side and then as a star legal scholar at Harvard, Obama learned early on the important skills of bringing opposing sides together and maneuvering around political foes. By the time he entered public service as an Illinois state legislator in 1997, he was already seen as a formidable politician.

Throughout this year's campaign, Obama strove to define himself to a public that was both leery of his Muslim-sounding name and his relative inexperience, and by the fall he appeared to have made headway in both areas. He outspent and out-organized McCain even in states considered solidly red, marking a stark contrast to the losing Democratic campaign of 2004, when Sen. John Kerry was overwhelmed by Bush's fundraising machine and portrayals of him as elitist and stiff.

McCain, for his part, had a base of support from conservatives who viewed him as best to continue what they believed was hard-fought progress in the war in Iraq and on national security matters in the post 9/11 world.

And he electrified the GOP base - evangelical Christians, concerned with issues like abortion and the makeup of the Supreme Court - by choosing as his vice presidential candidate Palin, the governor of Alaska and a church-going mother of five.

Especially compared with Obama's selection of Biden, a veteran of three decades in Washington as a senator from Delaware, it was a roll of the dice. McCain's gamble was that the relatively unknown Palin's energetic personality and reformer persona would trump her national inexperience.

But that inexperience showed in Palin's limited media interviews, when she gave several stumbling answers, and by the end of the campaign polls indicated that she was helping McCain only among ardent conservatives.

For Obama's part, the key tactical decision in the campaign may have been his decision to opt out of public financing. Republicans derided it as a broken promise to abide by spending limits. But the move allowed Obama to raise hundreds of millions from smaller donors on the Internet, and to splurge in the campaign's final days on such luxuries as a half-hour of time on broadcast and cable TV for an infomercial.

In the end, it came down to what it always does in presidential elections: a gut feeling among voters for who would be better in a crisis, and who best represents the future of the nation.

Given the scope of crises facing the country, the intensity level of this year's electoral battle was not just unsurprising. It was a given.

With that in mind, Obama said Tuesday that one of his challenges will be to unite those who fought so bitterly across the land.

"I may not have won your vote tonight, but I hear your voices," he said in Chicago. "And I will be your president, too."